Small piece folder



Dec. 23, 1969 H. .1. WEIR 3,485,491

SMALL PIECE FOLDER Filed May 17. 1967 I ll 4 2 3 &5 ,0 Q l 1 24 fia .5

United States Patent U.S. Cl. 270--68 2 Claims ABSTRACT OF THE DISCLOSURE A buckle folding machine having a conveyor and an overhead stop plate, a folding plate operable for clamping the leading edge of an article moving with the conveyor against the stop plate, the folding plate including an underside engagement member extending across the conveyor, and guide bar means upstream of the stop plate and extending below the stop plate in adjacent but spaced relation to the folding plate for restricting the radius of bow formed in the article, whereby thetrailing part of the article is carried by the conveyor downstream of the stop plate and the article is constrained to bend around the folding plate engagement member until the folding plate is dropped to release the leading edge whereupon the engagement member rests on the upper layer of the article as the article is moved away by the conveyor.

The invention relates to laundry folding machines and in particular to the kind of laundry folding machine in which the leading edge of an article to be folded is fed on to a movable folding plate; the folding plate moves upwards to clamp the leading edge against a stop plate; the following part of the article is fed forward beneath the plates on a moving conveyor and the folding plate is dropped to release the leading edge on to the trailing part of the article so that a fold is effected thereby. Usually, but not necessarily, the article is folded in half in this way, the timing being such that the leading edge is dropped on the trailing edge.

Difficulty is experienced in this type of folder when the article to be folded is short and/or stiff. Articles such as pillow-cases and table linen which are usually finished in the laundry process by being dressed are particularly difficult to fold. The reason is that in being folded in the manner described above the article takes the form of an S and has two curves, each of which, if the article is short and stiff, assumes as great a radius as possible. It is difiicult with articles of this nature to achieve sufficient accuracy in the folding since the curves in the article tend to interfere with the clean dropping of the leading edge from the folding plate. It is not readily possible to compensate for the errors so caused by adjustment of the timing device since the lengths of the curved portions are indeterminate and in any event dressed articles may be interposed in the folding sequence with non-dressed artia cles or with large articles such as sheets which do not assume curves of appreciable size when being folded. An object of the invention is to provide a folding machine which is particularly suitable for folding short and relatively stiff articles.

According to the invention, in a folding machine of the kind referred to there is provided an engagement member on the underside of the folding plate, the arrangement being such that when the folding plate is dropped to release the leading edge the engagement member rests on the article as the article is drawn away by the conveyor. This arrangement ensures that as the folding plate is dropped the leading edge tends to be drawn free in a positive manner by the conveyor acting in conjunction with the engagement member.

3,485,491 Patented Dec. 23, 1969 The engagement member should offer the minimum of drag to the article and although it is envisaged that it may comprise a free running roller or set of Wheels mounted to rotate on an axle runnnig parallel and near the edge of the folding plate it is preferably constituted by a smooth shoe or set of shoes. Preferably the shoe is formed by a curved metal sheet which may be integral with the folding plate.

The invention allows the provision of a further improvement which removes errors in folding due to the indeterminate length of the curve which is assumed by the article near the leading edge. This improvement is a further feature of the invention and lies in the provision of a guide member which is fixed near and slightly below the stop plate and which runs parallel to the edge of the folding plate. Conveniently, the guide member is in the form of a bar or is the lower edge of a plate mounted on the stop plate and its function is to restrict the size of the curve assumed by the article near the leading edge when it is clamped. As the leading edge is picked up the bow in the article which is formed is brought against the guide member which thereby keeps the size of the bow below a predetermined limit. The provision of the engagement member in accordance with the invention allows the guide member to be used without risk of affecting the accuracy of the fold by interfering with the withdrawal of the leading edge of the article from the folding plate.

When the article has been folded once by the method described above it is often necessary to fold it again and usually this second fold is effected by pinching the article, usually at its centre point, between a pair of contra-rotating rollers which draw the article therethrough and thereby effect the fold. Hitherto the conveyor has terminated at its forward end in a substantially horizontal run and the contra-rotating rollers have been positioned slightly beyond the end of the conveyor and below the conveyor, the articles being allowed to drape over the end of the conveyor as it moves and hand before the contra-rotating rollers. A tucking blade is positioned im mediately beneath the end of the conveyor and is arranged to be projected forwards at the appropriate time so as to tuck the centre part of the article between the rollers. This arrangement has the disadvantages when the articles are short and stiff and particularly when such articles have already been folded once since effectively they are then even shorter and stiffer. The tendency of such articles is to project rigidly beyond the end of the conveyor instead of falling over the end. Thus there is the risk that the article will be projected over the rollers without falling between the conveyor and the rollers or at best, if the leading edge of the article does fall between the conveyor and the rollers, there is a bow as the article is bent which does not conform to the conveyor and which interferes with the proper timing of the tucking blade. An object of a further feature of the invention is to provide a device which performs an improved second fold.

According to a further feature of the invention the conveyor terminates at its forward end in a flat run which i inclined downwardly, a pair of contra-rotating rollers is disposed immediately above the inclined run at the lower end thereof with their axes in a plane parallel therewith, and a tucking blade is provided immediately beyond the lower end of the inclined run to effect the tucking of the article between the contra-rotating rollers at a predetermined time.

Preferably there is provided a guide plate co-planar with the inclined run and spaced a short distance beyond the lower end thereof and the tucking blade is, a thin plate which moves longitudinally in the narrow gap between the guide plate and the inclined run. There is an additional advantage that with the contra-rotating rollers appropriately spaced above the inclined run it is found that the leading bow in the already folded article tends to be flattened thereby, so improving the fold.

The invention will further be described with reference to the accompanying drawing of which:

FIGURE 1 is a diagram illustrating at a, b and respectively three stages in the folding of an article in a folding machine of the kind referred to;

FIGURE 2 is a schematic diagram illustrating at a and b two stages in the folding of an article in a machine in accordance with the invention;

FIGURE 3 is a diagram illustrating a stage in the folding of an article in a modified machine in accordance with the invention;

FIGURE 4 is a schematic side elevation of part of a folding machine according to a preferred embodiment of the invention; and

FIGURE 5 is a diagram illustrating the mechanism according to a feature of the invention by which the second fold may be effected.

Referring to FIGURE 1 there is shown at a a conveyor 1 moving in the direction indicated by the arrow. A fold plate 2 is pivoted at 3 and is coupled to a pneumatic ram (not shown) which controls the movement of the plate about pivot 3 between the lowermost position shown and an uppermost position in which plate 2 contacts a stop plate 4, The conveyor 1 is in the form of a set of parallel spaced bands which move together and there is provided a set of movable fingers 5 which are pivoted at 6 and controlled by a pneumatic ram (not shown) to move between the hands up to the position shown in order to guide on to plate 2 the leading edge 7 of an article 8 to be folded. When the leading edge is in the position shown, plate 2 is moved up to clamp the leading edge against stop plate 4. At the same time fingers 5 are allowed to fall beneath the conveyor so as not to interfere with the further movement of the article.

FIGURE 1b shows the position when the following part of the article is fed beneath the folding plates. The article shown is assumed to be a starched pillow case and it will be seen that two bows 9 and 10 are formed therein as a result of the reluctance of the pillow case to bend. The next stage of the folding operation is shown in FIG- URE 10 where it is seen that the folding plate 2 has been lowered in order to allow the leading edge 7 of the article to drop. It will be seen that the leading edge 7 of the article overlaps the trailing edge 11 by an appreciable extent, this representing an error in the fold which is due to the difficulty in accurately timing the dropping of the leading edge owing to the indeterminate length occupied by the curves in the pillow-case and in particular by bow 10.

FIGURE 2 shows at a a view corresponding to FIG- URE 1b but in which the movable folding plate 2 has fixed on its underside a felt covered roller 12 which is free-running and which is arranged close to and parallel the edge of the plate. The pick-up of the article by the folding plate and the stage illustrated at FIGURE 2a are no different from the first two stages illustrated in FIG- URES 1a and b. However, reference to F'IGURE 2b shows the position corresponding to FIGURE 10 in which the folding plate 2 has been dropped to release the leading edge. In FIGURE 2b the arrangement is such that the roller 12 rests on the article as it is fed forward by the conveyor. This has the effect of constricting, to a certain extent, the movement of the leading edge 7 of the article and this is found to have the effect of drawing the leading edge from the clamped position more positively and consistently so that the folding of the articles in response to the fixed timing of the machine is more accurate.

FIGURE 3 shows a preferred form of the invention in which, in addition to roller 12, there is provided a fixed guide bar 13 which runs across the machine parallel to the edge of plate 2 and positioned slightly below the fixed stop plate 4. The arrangement is such that as the leading edge of the article is picked up the how 10, which tends to be formed as the article is moved forward, is restricted in radius by abutment of the article against the bar 13. In this way even better folding accuracy is obtained. The use of roller 12 in conjunction with bar 13 is particularly advantageous since this overcomes the etfect of the interference by the bar with the withdrawal of the leading edge of the article from the folding plates.

Referring to FIGURE 4 there is shown a preferred embodiment of the invention in which the folding plate 2 is a hollow structure made of 16 gauge alloy or stainless steel bent to the configuration shown. The lowermost part of the folding plate is constituted by a curved shoe 14 and the folding plate is allowed to rest on the trailing part of the article as it is drawn along, the smooth shoe sliding over it. The shoe extends for the full width of the conveyor so that its ends do not interfere with the edges of the article. Plate 2 pivots about axis 3 and is controlled in its movement by an air ram 15. Plate 2 is shown in its lowermost position, its uppermost position being indicated at 211. The lift fingers 5 are shown in their uppermost position, their lowermost position being indicated at 5a.

The stop plate has a pad 16 of material which offers some grip for the leading edge of the article. Fixed to the plate and extending across the full width of the conveyor is a substantially vertical plate 17, the lower edge 18 of which constitutes a guide member which performs the function of guide bar 13 of the FIGURE 3 arrangement.

Referring to FIGURE 5 there is shown the end part of conveyor 1 which, in accordance with a feature of the invention, is provided with a downwardly inclined straight run 19. This run is inclined at an angle of about 45 to the vertical. At the lower end of run 19 and positioned slightly above the conveyor there is provided a pair of contra-rotating rollers 20 and 21 which rotate in the directions indicated by the arrows. Rollers 20 and 21 are arranged so that the nip between them is just beyond the lower end of run 19. A guide plate 22 is provided coplanar with and beyond the lower end of run 19 and in the gap between run 19 and the guide plate there is a tucking plate 23 which extends across the width of the conveyor and which is movable by an air ram (not shown) in a linear direction indicated by the arrows.

When a folded article, illustrated at 24 is fed by the conveyor down the inclined run 19 the rollers 20 and 21 engage the upper part of the leading bow 25 in the article and thereby flatten this how to some extent. The spacing of rollers 20 and 21 from the plane of run 19 is of the order of 1 /2". When the mid-point of the article has reached the level of the fold blade 23 the pneumatic ram is operated and the mid-point is tucked between rollers 20 and 21 which draw the article through and pass it with a second fold formed thereby on to a table 26.

Conveniently, the timing for the various folding operations is effected, in conjunction with sensor devices for sensing the position of the article as it moves on the conveyor, by a timing device of the form described and illustrated in US. Patent 3,266,794.

I claim:

1. A buckle folding machine comprising a conveyor for moving an article along a path, an overhead stop plate, a folding plate operable for clamping the leading edge of the article against the stop plate, said folding plate including an underside engagement member extending across the conveyor, and guide bar means upstream of the stop plate and extending below the stop plate in closely adjacent but spaced relation to the folding plate for restricting the radius of bow formed in the article, whereby the trailing part of the article is carried by the conveyor downstream past the stop plate and the article is constrained to bend around the folding plate engagement member until the folding plate is dropped to release the leading edge whereupon the engagement member rests on the upper layer of the article as the article is moved away by the conveyor.

2. A buckle folding machine according to claim 1, wherein the engagement member comprises a smooth shoe curved in a convex manner from its upper edge substantially normal to the folding plate throughout approximately a quadrant with its lower edge substantially tangential to the conveyor.

References Cited UNITED STATES PATENTS Sjostrom 27068 X 6 3,310,207 3/1967 Gore 270-66X 3,339,914 9/1967 Grantham 270-85 X FOREIGN PATENTS 987,743 3/1965 Great Britain. 1,358,191 3/1964 France. 1,432,525 2/1966 France.

EUGENE R. CAPOZIO, Primary Examiner 10 PAUL V. WILLIAMS, Assistant Examiner US. Cl. X.R. 

